Patrick McGilligan (12 April 1889 – 15 November 1979) was an Irish lawyer and Cumann na nGaedheal/Fine Gael politician.
McGilligan was born in Coleraine, County Londonderry, Ireland. He was educated at St. Columb's College, Derry, at Clongowes Wood in County Kildare and at University College Dublin.
He joined Sinn Féin but was unsuccessful in his attempt to be elected as a MP in 1918. McGilligan was called to the bar in 1921.
He was elected as a Cumann na nGaedheal TD for the National University of Ireland at a by-election held on 3 November 1923. Between 1924 and 1932, McGilligan served as Minister for Industry & Commerce. In 1927, he set up the Electricity Supply Board (ESB), and also the Agricultural Credit Corporation. That same year McGilligan also took over the External Affairs portfolio following the assassination of Kevin O'Higgins by the anti-Treaty elements of the IRA as revenge for O'Higgins' support for the execution of Republican prisoners during the Irish Civil War (1922-23). In this position he was hugely influential at the Committee on the Operation of Dominion Legislation and at the Imperial Conference in 1930 (jointly with representatives of Australia, Canada, New Zealand, South Africa and the United Kingdom). The Statute of Westminster that emerged from these meetings gave greater power to dominions in the Commonwealth like the Irish Free State.
During his period in opposition from 1932 to 1948, he built up a law practice and became professor of constitutional and international law at University College, Dublin, and when the National University of Ireland representation was transferred to the Seanad in 1937, McGilligan was elected as TD for the Dublin North West constituency. In 1948, McGilligan was appointed Minister for Finance in the first Inter-Party Government. As Minister for Finance he undertook some major reforms. He instigated a new approach where Government invested radically in capital projects. Colleagues however complained of his frequent absence from the Cabinet table and the difficulty of contacting him at the Department of Finance Between 1954 and 1957 he served as Attorney General, a job in which as he admitted he felt far more at home than as Minister for Finance. He retired from Dáil Éireann at the 1965 general election, having served for over 40 years.
Patrick McGilligan died in Dublin on 15 November 1979. A later Attorney General, John M. Kelly, in the preface to The Irish Constitution (1980) noted the remarkable number of senior judges who were former students of McGilligan and suggested that given his own firm belief in the value of judicial review he deserves much of the credit for the remarkable development of Irish law in this field since the early 1960s.